Image projecting device and method

ABSTRACT

An image projecting device is presented. The device comprises an SLM pixel arrangement; and two lens arrays. The lens arrays are respectively located at opposite surfaces of the SLM pixel arrangement and are integral with the SLM pixel arrangement, forming together with the SLM pixel arrangement a common SLM unit. Each lens in one array and a respective opposite lens in the other array are associated with a corresponding one of the pixels. Each of the lens arrays is implemented in a polymer spacer and is either spaced from the corresponding surface of the opposite surfaces of the pixel arrangement a distance substantially not exceeding 50 μm or is in physical contact with the respective surface. The device also comprises a light source system operable to produce an incident light beam of a predetermined cross section corresponding to the size of an active surface of the SLM pixel arrangement; and a magnification optics.

FIELD OF THE INVENTION

This invention relates to a compact-size image projecting device andmethod.

BACKGROUND OF THE INVENTION

Microdisplays are miniaturized displays, typically with a screen size ofless than 1.5″ diagonal. Microdisplays are commonly used in dataprojectors, head mounted displays, and in the traditional viewfinders ofdigital cameras. Microdisplays can be implemented within compactprojectors, in viewfinders of handheld Internet appliances and in mobilephones for Web surfing and videoconferences, because full computerscreens can be viewed.

Most microdisplays use a light-valve made of a silicon chip as thesubstrate material. The chip also houses the addressing electronics (atleast an active matrix with integrated drivers), usually implemented instandard CMOS technology which allows very reliable and stable circuits,as well as very small pixel pitches (down to 10 μm or even somewhatsmaller), as well as high display resolutions.

There are known reflective and transmissive light valves. Reflectivelight valves bounce light off the displayed image into the viewer's lensor the projection lens. Transmissive light valves are similar tobacklit, portable computer screens using LCD (Liquid Crystal Display)and EL (electro-lumination) technologies. Common reflective light valvesare based on Liquid Crystal On Silicon (LCOS) and tilted micro-mirrors(DMD). Common transmissive light valves are based on Active-MatrixLiquid Crystal Displays (AMLCD).

Projectors that use transmitting microdisplays as mentioned abovetypically comprise an optical path that includes a light source and aSpatial Light Modulator (SLM), in which a beam shaping optic componentas well as a polarizing component are disposed between them. Anotherpolarizing component and a magnifying optic component are generallydisposed between the SLM and the projection surface. The SLM is coupledto a video processing driver to produce the image modulation of thelight according to an input signal.

Common optical difficulties in the design of known projectors based onmicrodisplay are: low energy efficiency; low brightness andnon-uniformity of the output image due to the source non-uniformintensity distribution (i.e. Gaussian distribution over the SLM surface)and intensity losses; low focus depth of the output image. In laserbased projectors, the “speckle” phenomena of a Laser source according towhich, a granular pattern of light pervade the image, is also atechnical difficulty. Other common difficulties directly related to theoptical difficulties and to the hardware implementation are: size,weight, optical complexity, power consumption and the mobility of theoverall projecting device.

Different methods and devices addressed to overcome one or more of theabove-mentioned difficulties are disclosed by the following.

U.S. Pat. No. 5,971,545 discloses a compact and energy efficientprojection display utilizing a reflective light valve. The output beamsof the light sources are received by at least one spatial lightmodulator. The modulated output beams are collimated and combined. Aprojection lens receives the collimated and combined output beams anddirects them towards a projection screen. Energy efficiency is achievedby using sequentially strobed RGB light sources instead of a white lightsource.

U.S. Pat. No. 5,777,789 discloses an optical system for high-resolutionprojection display, consisting of reflection birefringent (doublerefractive) light valves. The LCD projector comprises a polarizing beamsplitter, color image combining prisms, illumination system, projectionlens, filters for color and contrast control, and a screen. Theillumination system includes a light source such as a metal-halide arclamp, an ultraviolet and infrared filter or filters positioned in theoptical path from the light source for filtering out the infrared andultraviolet light emitted from the light source, a light tunnel forproviding uniform light intensity, and a relay lens system formagnifying the illumination system output plane and imaging said planeonto the liquid crystal light valves.

U.S. Pat. No. 5,975,703 discloses an image projection device having anSLM and a polarized source system. The optical system uses polarizedlight manipulated by at least one of a conicoid, or plane opticalelements to effect a folded mirror system to project an image onto ascreen by utilizing input light components of more than one state ofpolarization, thus reducing intensity losses over the optical system dueto polarization filtering. The system supplies light components ofsubstantially orthogonal polarizations for separate areas of the SLM tobe output onto a projection screen.

U.S. Pat. No. 6,183,092 discloses a laser projector which includes alaser apparatus and a reflective liquid-crystal light valve capable ofspeckle suppression through beam-path displacement by deflecting thebeam during projection, thereby avoiding both absorption and diffusionof the beam while preserving pseudocollimation (noncrossing rays). Thelatter, in turn, is important to infinite sharpness. Path displacementis achieved by scanning the beam on the light valves which also providesseveral enhancements—in energy efficiency, brightness, contrast, beamuniformity (by suppressing both laser-mode ripple and artifacts), andconvenient beam-turning to transfer the beam between apparatus tiers.The deflection effect is performed by a mirror mounted on a galvanometeror motor for rotary oscillation; images are written incrementally onsuccessive portions of the light valve control stage (either optical orelectronic) while the laser “reading beam” is synchronized on the outputstage. The beam is shaped, with very little energy loss to masking, intoa shallow cross-section which is shifted on the viewing screen as wellas the light valves. Beam-splitter/analyzer cubes are preferred overpolarizing sheets. Spatial modulation provided by a light valve andmaintained by pseudocollimation enables imaging on irregular projectionmedia.

U.S. Pat. No. 5,517,263 discloses a compact size projection system whichincludes a bright light source of polarized light, and a spatial lightmodulator, having an alignment layer, to modulate the polarizedprojection light, wherein the bright polarized light source is alignedwith the alignment layer to permit the polarized light to passtherethrough without the need for unwanted light blocking polarizers.The use of a polarized laser source together with its proper alignmentwith the light valve, enables substantially all of the laser light beamsto be utilized by the SLM to form the projected image. Without the useof filters and/or polarizers with the light valve, the intensity lossesof the laser optical output are thus reduced. Furthermore, the lightemanating from a laser is polarized, and thus, there is no need forpolarizing filters, which would otherwise reduce the laser light energy.

U.S. Pat. No. 5,704,700 discloses a laser illuminated and SLM-basedprojection system that includes a microlaser array coupled with a beamshaper to produce a bright (i.e. having a uniform intensitydistribution) projection light beam to be impinged over the SLM. Thebeam shaper includes a binary phase plate, a microlens array arrangementor a diffuser arrangement to modify the shape and intensity profile ofthe projection light beam. The laser light illuminating the light valvethus has a uniform intensity distribution for projecting an extremelybright image, and is confined substantially to the pixel portion of thelight valve.

SUMMARY OF THE INVENTION

There is a need in the art to facilitate projecting of images byproviding a novel miniature projector device and method.

The device of the present invention is lightweight and highly efficient,and is capable of utilizing a high-ratio polarized light source,high-efficiency SLM performing digital processing of data to be imagedso as to significantly reduce the speckles' associated effects, as wellas performing digital processing of a projected image to improve itsuniformity.

According to one broad aspect of the present invention, there isprovided an image projecting device comprising a light source systemoperable to produce an incident light beam of a predetermined crosssection to be incident onto the active surface of a spatial lightmodulator (SLM) unit formed by an SLM pixel arrangement, saidpredetermined cross section of the incident beam corresponding to thesize of said active surface; and a magnification optics accommodated atthe output side of the SLM unit; the device being characterized in thatsaid SLM unit comprises first and second lens arrays at opposite sidesof the SLM pixel arrangement, such that each lens in the first array anda respective opposite lens in the second array are associated with acorresponding one of the SLM pixels.

The device of the present invention may utilize a transmissive SLM typethat does not require polarization of the light, or alternatively mayutilize an SLM of the kind operating with specifically polarized light.In the latter case, the device is designed so as to provide specificpolarization of the SLM input and output light. This can be implementedby using a polarizer unit at the output of the SLM and either using aninput polarizer or a light source of the kind generating high-ratiopolarized light. The input polarizer may be part of the light sourcesystem or of the SLM unit.

The light source system may comprise an optical arrangement operable toprovide substantially uniform intensity distribution within thecross-section of the incident light beam. This optical arrangementincludes a diffractive element (commonly referred to as “top-hat”)operable to modify the beam intensity distribution to produce thesubstantially uniform intensity distribution of the beam within itscross-section.

Preferably, if the use of polarized light is required, the light sourceused in the device of the present invention is of the kind generating ahigh-ratio polarized light beam (thereby eliminating the use of apolarizer at the input side of the SLM unit), and preferably also of thekind generating the light beam of the cross section substantially of thesize of the active surface of the SLM unit (thus enabling theelimination of the beam shaping optics) or alternatively equipped with abeam shaping optics to provide the desired beam cross section.

According to another broad aspect of the present invention, there isprovided an image projecting device comprising a light source systemoperable to produce a light beam to impinge onto an active surface of aspatial light modulator (SLM) unit formed by an SLM pixel arrangement,said incident light beam being linearly polarized, having apredetermined cross section corresponding to the size of said activesurface; and a polarizer unit and a magnification optics accommodated atthe output side of the SLM with respect to the direction of lightpropagation through the device, the device being characterized in that:

said light source system comprises a light source generating saidlinearly polarized light beam having the cross section substantiallyequal to the size of the active area of the SLM unit; and

said SLM unit comprises first and second lens' arrays at opposite sidesof an SLM pixel arrangement, such that each lens in the first array anda respective opposite lens in the second array are associated with acorresponding one of the SLM pixels.

Preferably, the above device also comprises a diffractive opticsaccommodated in the path of light propagating towards the SLM unit toprovide substantially uniform intensity distribution of the incidentlight beam within said cross section.

Preferably, the device of the present invention comprises an imageprocessor system (control unit) operable to carry out at least one ofthe following: applying digital processing to data indicative of animage to be projected so as to avoid or at least significantly reducethe speckle-associated effects in the projected image; processing ofdata indicative of the projected image to correct for non-uniformitiesin the light intensity; and analyzing data indicative of theenvironmental condition to adjust the intensity and/or the color mixtureof the incident light beam.

Thus according to yet another aspect of the present invention, there isprovided an image projecting device comprising a light source systemoperable to produce a light beam to impinge onto a active surface of aspatial light modulator (SLM) unit formed by an SLM pixel arrangement,said incident light beam being linearly polarized and having apredetermined cross section corresponding to the size of said activesurface, and a polarizer unit and a magnification optics accommodated atthe output side of the SLM with respect to the direction of lightpropagation through the device, the device being characterized in thatit comprises an image processor system operable to carry out at leastone of the following: (i) applying digital processing to data indicativeof an image to be projected so as to reduce effects associated withcreation of speckles in the projected image; (ii) processing of dataindicative of the projected image to correct for non-uniformities in thelight intensity; and (iii) analyzing data indicative of an environmentalcondition to adjust at least one of the intensity and color mixture ofthe incident light beam.

The device of the present invention may be operable to provide colorimages. This can be implemented by utilizing three separate SLM pixelseach for at corresponding one of three primary colors, or by utilizingthe same SLM pixels for all the primary colors, but providing timemodulation of the color light components. The analysis of the dataindicative of the environmental condition may alternatively oradditionally be aimed at adjusting the color mixture of the incidentlight beam.

The device of the present invention can be used with any conventionalvideo generating device to project images onto an external screensurface. The device can be operable to project the same image with twodifferent angles of projection, thereby enabling observation of the sameimage by two different observers, and also allows for private operationof the respective one of the images by each of the observers through hisviewing area.

The technique of the present invention allows for combining imagesprojected by several micro-projectors of the present invention, therebyallowing the creation of a large combined image; projecting the imageonto a concaved screen surface; and creation of stereoscopic images byusing two micro-projectors or the single micro-projector equipped with arotating mirror.

The present invention, according to its yet another aspect provides amethod for projecting an image comprising:

-   -   (a) creating an incident light beam having a predetermined cross        section corresponding to a size of an active surface of a        spatial light modulator (SLM) unit formed by an SLM pixel        arrangement and directing said incident light beam towards said        active surface;    -   (b) passing said light through the SLM unit having first and        second lens' arrays at opposite sides of the SLM pixel        arrangement, each lens in the first array and a respective        opposite lens in the second array being associated with a        corresponding one of the SLM pixels, concurrently operating the        SLM pixel arrangement with an imaging signal representative of        an image to be projected;    -   (c) passing modulated light emerging from the SLM unit through a        magnifying optics to be projected into a projecting surface.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carriedout in practice, preferred embodiments will now be described, by way ofnon-limiting example only, with reference to the accompanying drawings,in which:

FIG. 1 is a schematic block diagram of a projecting device according tothe invention showing the main optical components a light propagationscheme;

FIG. 2 more specifically illustrates the operation of a diffractingelement (top-hat) used in the device of FIG. 1;

FIG. 3A illustrates the front view of the windowed structure of an SLMused in the device of FIG. 1;

FIG. 3B illustrates the structure of a lenslet array used with the SLMof FIG. 3A;

FIGS. 4A and 4B show beam propagation schemes through, respectively, theSLM of FIG. 3A and the SLM-with-lenslet array of FIG. 3B;

FIG. 4C illustrates a specific example of the SLM unit construction;

FIGS. 5A and 5B demonstrate the principles of intensity losses caused byusing unpolarized and polarized light sources, respectively;

FIG. 6 more specifically illustrates an image processor unit accordingto the invention used with the device of FIG. 1 to improve the qualityof the projected image;

FIGS. 7A and 7B more specifically illustrate the operation of the deviceof FIG. 6 to improve the brightness within the projected image;

FIGS. 8A and 8B more specifically illustrate the operation of the deviceof FIG. 6 aimed at solving the speckles-associated problem;

FIG. 9 is a flow diagram of the main operational steps in a methodaccording to the invention aimed at color-mixture modulation of lightinputting the SLM;

FIGS. 10A to 10E schematically illustrate different examples of theimplementation of projection of color images suitable to be used in thedevice of the present invention; and

FIGS. 11A to 11H schematically illustrate different applications of theprojecting device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of a projecting device 1 accordingto the invention showing the optical components of a light propagationscheme. The device 1 comprises a light source system LSS including alight source 2 generating a collimated light beam 4, an opticalarrangement including a diffractive element 34 (“top-hat”) operable toaffect the intensity distribution of the beam 4 to produce substantiallyuniform intensity distribution of the beam 4 within its cross section,and a beam shaping optics (beam expander) 6 that affects the crosssection of the beam 4 to be substantially equal to the size of an activesurface defined by a pixel arrangement 5 (the so-called “windowedstructure”) of an SLM unit 12 (such as the liquid crystal based SLMModule RS170 commercially available from Kopin Corporation, USA).

It should be noted that the provision of the beam expander 6 isoptional, and the same effect can be achieved by providing anappropriate light source, for example, a laser diode/DPSS laser modulewith a beam diameter of 6 mm to cover the image modulation area on theSLM.

It should also be noted that the SLM unit may be of the king operatingwith randomly polarized light. Alternatively, the SLM unit may be of thekind operating with specifically polarized light. In this case, thelight beam impinging onto the SLM pixel arrangement has a specificlinear polarization, and the device comprises an output polarizer(analyzer) 18 shown in dashed lines since its provision is optionaldepending on the kind of SLM used in the device. The polarizer 18 has apreferred orientation of the plane of polarization either similar tothat of the incident light beam 4 or 90°-rotated, and therefore blockseither the part of light that has been rotated by the SLM, or the partthat has not been affected by the SLM. As for the polarization of theincident light beam, it is preferably achieved by using the light sourceof the kind generating high-ratio polarized light, but can, generally,be achieved by using a light source generating a randomly polarizedlight and using a separate polarizer (not shown) at the input side ofthe active surface 5. This input polarizer can be a part of the lightsource system, a part of the SLM unit, or can be a stand-alone unitaccommodated between the light source and the SLM unit.

Thus, in the example of FIG. 1, the SLM is of the kind operating withpolarized light, the light source generates high polarization ratiolight, and the output polarizer is used. The term “high polarizationratio” is typically referred to as that of about 1:50, 1:100 polarizedlight or above, and can for example be achieved with a laser diode andDPSS laser modules, such as the GMC-532-XF5 laser module seriescommercially available from Lasemate Corporation USA.

The construction of the SLM pixel arrangement 5 is known in the art andtherefore need not be specifically described except to note that itcomprises a two-dimensional array of active cells (e.g., liquid crystalcells) each serving as a pixel of the image and being separatelyoperated by a modulation driver 11 to be ON or OFF and to perform thepolarization rotation of light impinging thereon, thereby enabling toprovide a corresponding gray level of the pixel. Some of the cells arecontrolled to let the light pass therethrough without a change inpolarization, while others are controlled to rotate the polarization oflight by certain angles, according to the input signal from the driver11.

The SLM unit 12 further comprises a first lenslet array 10 at the inputside of the pixel arrangement and a second lenslet array 14 at theoutput side of the pixel arrangement. Practically, the lenslet arrayscan be integral with the pixel arrangement being mounted onto theopposite surfaces thereof. The construction and operation of the SLMunit with lenslet arrays will be described more specifically furtherbelow with reference to FIGS. 3A–3B and 4A–4C. The lenslet array is atwo-dimensional array of miniature lenses that matches the array ofactive cells of the SLM, such that each lens from the array 10 and therespective opposite lens from the array 14 are associated with thecorresponding one of the active cells. The lenslet array 10 thusclusters the light beam 8 to correspond to the image modulation areawithin the active surface 5 of the SLM elements by splitting the lightbeam impinging thereon into a plurality of components and focusing eachcomponent by the respective lenslet to the respective pixel (i.e. eachlenslet corresponds to a single pixel), thus improving the lightefficiency of the process.

Thus, the incident light beam (e.g., linearly polarized light beam) ofthe substantially uniform intensity distribution 4 is expanded resultingin a beam 8 with the cross section substantially equal to the size ofthe active surface of the SLM. The beam 8 passes through the lensletarray 10 resulting in the clustered light that passes through the SLMpixel arrangement and is modulated in accordance with the image to beprojected. The modulated light emerging from the SLM is collected by thesecond lenslet array 14, that cancels the clustering effect of the firstlenslet array 10, thus producing a beam 16 having a uniform crosssection as that of the beam 8 before passing through the first lensletarray 10. The operation of the SLM unit will be described morespecifically further below with reference to FIGS. 3A–3B and 4A–4B.

Further provided in the device 1 is a magnification optics 22 located inthe optical path of light emerging from the SLM unit (or from thepolarizer 18 as in the present example) and propagating towards aprojecting (or screen) surface 26. Thus, the beam 16 passes through thepolarizer 18 that produces a polarized intensity modulated beam 20indicative of an image to be projected by the magnifying optics 22 ontothe screen surface 26. As known to those skilled in the art, a projectedimage 28 will stay in focus for a large variety of distances between theprojecting device 1 and the screen surface 26 due to the nature of thelight source and its coherence in the given optical path. Alternatively,when light is not coherent the focus can be manually adjusted by movingthe magnifying lens 22 along the optical path.

FIG. 2 more specifically illustrates the operation of the diffractingelement 34 (top-hat) used in the device of FIG. 1. The top-hat elementby itself does not form part of the present invention and itsconstruction and operation are generally known, and consists of thefollowing. A light source 30 that can be a laser diode or any othersource creates a light beam 32 in which the light intensity near theaxis of the beam is higher than that within the periphery of the beam(Gaussian intensity distribution). This beam is to be used for imaging(for example by the device 1 of FIG. 1) that requires substantiallyuniform light intensity distribution throughout the format of the image(i.e., within the cross section of the light beam). The diffractiveoptical element 34 is thus used to modify the beam intensitydistribution to produce a beam 38 of the substantially uniform intensitydistribution that can provide substantially uniform illumination of ascreen 36.

It should, however, be noted that the light beam arriving at theprojecting surface can still be somewhat non-uniform due to thelimitations of the top-hat component 34 (about 96% of transmittanceefficiency) and/or because of the non-uniform transmittance of the othercomponents in the optical path. Compensation for such non-uniformity canbe performed digitally by adjusting a control signal to every pixel ofthe pixel arrangement and providing an image-wise compensation bias, aswill be explained further below with reference to FIGS. 6 and 7A–7B.

Reference is now made to FIGS. 3A–3B and 4A–4B. FIG. 3A illustrates thefront view of the windowed structure of the SLM unit 12 used in thedevice of FIG. 1, and FIG. 3B illustrates the structure of the lensletarray 10 used with the SLM of FIG. 3A. FIGS. 4A and 4B show the beampropagation schemes through, respectively, the SLM of FIG. 3A and theSLM-with-lenslet arrays of FIG. 3B.

Thus, as shown in FIG. 3A, the pixel arrangement (windowed structure) 40of a typical SLM is a two-dimensional array of spaced-apart cells 42.Approximately 40% (varies from one SLM to another) of the total surfaceof the structure 40 is composed of the active cells 42 while the rest ofthe surface is composed of a frame 44 that serves for mechanical supportand control signals of the pixel array. FIG. 4A shows the side view ofthe pixel arrangement 40 and the propagation of a parallel light beam 50therethrough. As can be seen, a portion of the incoming light 50 isblocked by the frame partitions 44, and only the remaining portion ofthe light 50 gets through the active cells 42. Thus the fill factor(i.e., effective transmission) for this typical SLM structure isapproximately 40%.

FIG. 3B illustrates the structure of a lenslet array 46 to be used atopposite sides of the pixel arrangement 40 in the SLM unit according tothe invention in order to increase the fill factor of the SLM. Thelenslet array 46 is a two-dimensional array of miniature lenses 48 thatmatches the pixel arrangement 40 of active cells 42. Each lens 48 mayhave a square-like shape, and the adjacent lenses are tangent to eachother thus fills most of the surface defined by the lens array 46 (i.e.,fill factor of approximately 100%).

As illustrated in FIG. 4B, showing the pixel arrangement 40 with thefirst lenslet array 46 and the second lenslet array 46′, the firstlenslet array 46 is disposed at the input side of the pixel arrangement40 very close thereto (up to a physical contact) and the second lensletarray 46′ is disposed at the output side of the pixel arrangement 40also very close thereto, up to a physical contact. Practically, thefirst and second lenslet arrays can be integrated with the pixelarrangement 40 being mounted onto the opposite surfaces thereof. Eachlens 48 from the first array 46 and the respective opposite lens 48′from the second array 46′ are associated with the corresponding one ofthe active cells 42. Each of the lenses 46 is optically designed tofocus the corresponding component of the beam 50 onto a small areaaround its axis, at a distance of few microns behind the array. Thepitch of the lenses 46 is matched to the pitch of the active cells 42,so that there is one active cell 42 centered right behind each lens, andthe central point of the cell 42 is located in the back and front focalpoints of the respective lenslets 48 and 48′, respectively. The firstlenslet array 46 thus clusters the light beam 50 to correspond to thearea of the arrangement 40 (active surface of the SLM unit) by splittingthe light beam 50 impinging thereon into a plurality of components 64and focusing each component by the respective lenslet to the respectivepixel. The second lenslet array 46′ is substantially identical to thefirst lenslet array and is positioned opposite to the array 46 at theother side of the pixel arrangement 40. The second lenslet array mirrorsthe optical effect of the first array, thus causing a reverse opticaloperation on the beamlets 66 emerging from the active cells 42. Thesecond array 46′ diverge the individual beamlets 66 spatially modulatedby the arrangement 40 to create a light beam 80. The opticalcharacteristics of the lenslets in the arrays as well as the distancebetween the first and second arrays 46 and 46′ and the pixel arrangement40 can be determined by simple optical alignment methods known in theart so as to provide that the diameter of the beamlet 64 when reachingthe active cell 42 is smaller than the aperture of the cell 42, thus allthe light of the beamlet 64 passing through the active cell 42.

Thus, the total effect of the combination of the pixel arrangement 40with the first and second lenslet arrays 46 and 46′ is as follows: theincoming light beam 50 is divided by the passage through the lensletarray into separate focused beamlets 64, that then pass through thecells 42 of the pixel arrangement 40, where they are modulated accordingto the control signal (indicative of the data to be imaged) to produce aplurality of focused beamlets 66 emerging from the pixel arrangement.

The beamlets 66 pass through the lenslets 48′ that create therefrom theparallel beam 80 of spatially modulated light. As a result, the fillfactor of the combined arrangement (lenslet arrays and pixelarrangement) is substantially higher than that of the pixel arrangement40 by itself, and the total efficiency of the modulation process is thussubstantially improved. The provision of the lenslet arrays improves thetransmission efficiency of the SLM by up to 30% and more. It should beunderstood that when using the SLM with all active pixels, theefficiency of the SLM unit can be improved by a factor of 2 due to theuse of the lenslet arrays at both sides thereof.

As exemplified in FIG. 4C, the SLM unit may be of a 100 μm thickness,wherein the pixel arrangement (e.g., LC unit) has a thickness of 10 μmand each of the polymer spacings P₁ and P₂ has a thickness of 45 μm. TheSLM unit may be manufactured using stamping and hat embossingtechniques.

As indicated above, the device of the present invention preferablyutilizes a polarized light source. FIGS. 5A and 5B demonstrate theprinciples of intensity losses caused by using unpolarized and polarizedlight sources, respectively. FIG. 5A shows the basic optical pathsuitable to be used in a projector (or display) and utilizing a typicalnon-polarized light source 74. Such an optical path thus comprises thelight source 74, a first polarizer 81, an SLM 84 and a second polarizer96. The non-polarized light source 74 creates a light beam that can berepresented by two components 76 and 78 of the opposite linearpolarizations. Both components 76 and 78 impinge onto the firstpolarizer 81, and only one of them can pass therethrough while the otheris rejected away, depending on the orientation of the plane ofpolarization of the device 81. Thus, the energy of a polarized lightbeam 82 emerged from the polarizer 81 is half of the input energy of thenon-polarized light beam. The SLM 84 receives the polarized light beam82 and modulates it by an input signal 86 to affect the polarization ofcorresponding light components of the beam 82 according to the inputsignal 86. For the simplicity of demonstration, the SLM 84 isrepresented as an element consisting of two polarization areas 88 and90, i.e., two cells or pixels one of which 90 being currently operatedby the control signal 86 and the other 88 being not. Hence, a lightportion 92 that emerges from the area 88 has its original polarization,and a light portion 94 that emerges from the area 90 has itspolarization affected in accordance to the input signal 86, e.g., hasthe orthogonal polarization with respect to its original polarizationstate. Both light portions 92 and 94 impinge onto the second polarizer96 that transmits only light identical in polarization to thattransmitted by the first polarizer 81. Thus, only the light portion 92,the polarization of which was not effected by the SLM 84, can passthrough the polarizer 96, and the intensity of the output beam 98 ishalf of that emerging from the first polarizer, and practically aquarter of the light generated by the light source.

FIG. 5B shows the basic optical path for use in a projector (or display)and utilizing a high-ratio polarized light source as proposed by thepresent invention. To facilitate understanding, the same referencenumbers are used for identifying components that are common in theexamples of FIGS. 5A and 5B. Thus, the optical path of FIG. 5B comprisesa high-ratio polarized light source 75, an SLM 84, and a polarizer 96(the need for the first polarizer 81 of FIG. 5A be therefore eliminatedhere). Light 100 generated by the light source 75 is linearly polarized.A light portion 92 that emerges from the SLM area 88 not operated by acontrol signal has its original polarization, and the polarization of alight portion 94 that emerges from the SLM area 90 operated by thecontrol signal 86 is changed, e.g., to the orthogonal polarization. Bothlight portions 92 and 94 impinge onto the polarizer 96 that transmitsonly light with the polarization state identical to that produced by thelight source. Thus, only the light portion 92, the polarization of whichwas not effected by the SLM 84, can pass through the polarizer 96.Similar to the previous example of FIG. 5A, the intensity of the outputbeam 98 is half of that provided by both light portions 92 and 94.However, this intensity of both light portions 92 and 94, i.e., theintensity of light impinging onto the SLM 84 is that generated by thelight source, namely, is twice as much of the intensity of the SLM inputlight 82 in the example of FIG. 5A, due to the use of the polarizedlight source. Thus the optical efficiency of the optical path of FIG. 5Bis higher by a factor of 2 than that of FIG. 5A.

Turning now to FIG. 6, illustrating an image projecting device 3according to another embodiment of the invention. The same referencenumbers are used for identifying the common components in devices 1(FIG. 1) and 3. The device 3 additionally comprises a control unit CU(typically a computer device), wherein, in this specific example, themodulation driver 11 is a part of the control unit. The control unit CUthus comprises the driver 11 and a processor utility 330, and isassociated with an image recorder 332 and an environment sensor 334. Thedriver 11, that generates control signals (modulation signals) to theSLM pixel arrangement, is operable by a signal indicative of the imageto be projected (“image signal”). The image signal is generated by anappropriate signaling utility (not shown here) that may and may not be apart of the control unit of the projector device, and may typically be apart of an external computer device (such as PC, phone device, PDA,etc.) where the data to be images is produced. In this specific exampleof FIG. 6, the image signal is supplied to the driver 11 through theprocessor utility 330, but it should be understood that the image signalcan be supplied directly to the driver 11. The image recorder 332 is animaging device such as a video camera, which is oriented and operable togenerate data indicative of the projected image 28. The environmentsensor may include one or more sensing units detecting the environmentcondition of the kind defining the required intensity and/or colormixture of the projecting light, e.g., the light intensity sensor (suchas a CCD RGB/Temperature single pixel sensor) capable of detecting theintensity of ambient light in the vicinity of the screen surface 26 andgenerating corresponding data.

The processor 330 includes inter alia a controller CL, and three utilityparts (suitable software and/or hardware) U₁, U₂ and U₃ for processing,respectively, the image signal coming from the controller, the datacoming from the image recorder, and the data coming from the sensordevice. The utility U₁ is preprogrammed to analyze the image signal inaccordance with the SLM pixel arrangement so as to perform digital imagejittering and attenuation (changing of gray levels) on the pixelarrangement (via the driver 11) in order to reduce effects of specklesin the projected image, as will be described more specifically furtherbelow with reference to FIGS. 8A and 8B. The utility U₂ is preprogrammedto analyze the data indicative of the projected image 28 and apply adigital processing of the image signal to thereby compensate for thenon-uniformity of the light intensity (brightness) within the projectedimage. This is described below with reference to FIGS. 7A–7B. Theutility U₃ is preprogrammed to analyze the data indicative of theenvironment condition and modulate the laser source 2 accordingly toadjust either one of the intensity and color mixture, or both. Thus, theprovision of the control unit and associated sensor devices (e.g.,camera, RGB/Temperature sensor), as well as the digital processing ofthe image signal, improves the quality of the projected image and theenergy efficiency of the projecting device.

FIGS. 7A–7B exemplifies the operation of the projecting device equippedwith the processor 330 to provide digital compensation of a lightmodulated image on the target (screen surface). FIG. 7A shows the lightmodulated image 108 containing non-uniform areas, with over intensivespots of light 110. A digital mask 112 designed to decrease the lightintensity within the area 114 is applied to the light modulated image108 resulting in a final output image of uniform brightness intensity ona target 116. FIG. 7B illustrates a basic calibration procedure of thedigital mask. The processor 330 (controller CL) receives a pattern-imagesignal (generated either externally by a video generating device (PC,VCR, etc.) or internally in the controller CL), and generates a controlsignal indicative of the pattern image (Step I). This pattern-imagesignal is transmitted from the processor to the driver 11 (Step II) tooperate the SLM pixel arrangement accordingly to enable projection ofimages with the original non-uniformity in brightness. The lightdispersal of the projected images is projected on the screen surface (26in FIGS. 1 and 6). A digital camera (332 in FIG. 6), or any other kindof optical recording device, scans the projected image (Step III).Digital output data of the camera 332 indicative of the recorded imageis received by the utility (U₂ in FIG. 6), that analyzes this data andoperates together with the controller CL to compare the data indicativeof the recorded image with the generated image (created in accordancewith the original input signal), and if the images are identical, thecalibration result in the form of a final digital mask is generated. Ifthe lack of similarity in the signals is determined, an updated image isgenerated accordingly to obtain the final digital mask (steps IV and V).The controller CL then saves the calibration result (digital maskstatus) in the driver 11 in order to update the projecting device withthe correct parameters of brightness levels (step VI). It should beunderstood that the utility U₂ may not be a part of the processor, butbe a stand-alone image processing unit connectable to the imagerecording device 332 and to the processor 330.

FIGS. 8A and 8B more specifically illustrate the operation of the deviceaccording to the invention aimed at eliminating the speckle effect whichappears in the projected screen. As shown in FIG. 8A, an originalprojected image 240 appears as an image with granular nature, theso-called “speckle effect”. This effect is observed with highly coherentillumination, when the screen surface is not totally smooth. In order toeliminate this problem, the original image 240 is jittered and the graylevel is also attenuated by a maximum displacement of one pixel as itappears in a shifted projected image 242. Every pixel is now jitteredand attenuated with such velocity that the human eye is unable to noticethis effect. For example, an original pixel 244 is jittered to a newposition 246, so that this motion causes the coherence of theillumination to be at least partially destroyed, and the speckles “washout” during the projecting process, thereby producing a clear(speckles-free) image 248. The main operational steps of this procedureare shown in FIG. 8B. The original image (i.e., the image to beprojected) is grabbed from the driver 11 of the SLM, or from thecontroller CL as the case may be, (step A), and is processed by theutility U₁ to resize this image to free active pixel space used forjittering purposes (step B), thus leaving more extra space in thecorners and panels of the SLM pixel arrangement. Data indicative of theso-produced resized image is transmitted to the driver 11 (step C),where the image is shifted accordingly in a plane along twoperpendicular axis by shifting one or more image pixel to be in thepixel areas that were defined as area not in use, and modulated toprovide changes in gray level (step D). By this, a circular movement ofthe image on the SLM surface is provided in a high frequencycirculation, ensuring that the circulation process remains unnoticeableto the observer and at the same time ensuring that the image on the SLMsurface moves along the two axes repeatedly, resulting in the reductionof the speckle phenomenon viewed to the observer. It should be notedthat such parameters as the frequency of circulation, number of shiftedpixels, and the step of movement along either one of the two axes orboth is controlled by the given algorithm for different outcome resultsin different given situations.

FIG. 9 is a flow diagram of the main operational steps of the processor330 to meet the requirements of the environment by utilizingcolor-mixture modulation of light inputting on the SLM pixelarrangement. In the present example, the environment sensor is atemperature sensor (i.e., sensing the intensity of the ambient light).The processor utilizes the sensing data to enable optimization of thelight source total consumption by changing switching modulation of colormixture according to the surrounding light condition, thus receiving themost intensive image exposed to the human eye in the contrast of thesurrounding interfering light. This is implemented in the followingmanner:

The sensor absorbs room light temperature (in different wavelengths) inthe vicinity of the screen surface (step 1). Data indicative of theabsorbed light is received by the processor (utility U₃ in FIG. 6) thatcompares between the optimal (default) required image/temperature inoptimal surroundings and the light temperature sensed on the projectedsurface (step 2). If a lack of similarity is determined, the processorupdates color mixture modulation of the light source (step 3) incontrast to the optimal condition, and then allows for projecting theimages according to the new color modulation (step 4).

Reference is now made to FIGS. 10A–10E schematically illustratingdifferent implementation examples of projection of color images suitableto be used in the device of the present invention. FIG. 10A shows aschematic block diagram of the device according to one example of thisconcept and FIG. 10B shows one possible implementation thereof. FIG. 10Cshows a schematic block diagram of the device according to anotherexample, and FIGS. 10D and 10E show two possible implementations of thisexample. In the example of FIGS. 10A–10B, the primary colors R, G and Bare modulated via three optical paths, respectively, each having itsassociated SLM, while in the example of FIGS. 10C–10E, the primarycolors, R, G and B are modulated via the same optical path andconsequently the same SLM by utilizing the time beam modulator.

As shown in FIG. 10A in a self-explanatory manner, R, G, and B lightcomponents 250, 252 and 254 are generated by three laser sources,respectively, e.g., compact laser diodes with appropriate powers inorder to get a white source. Each light component is widened by itsassociated beam expander, generally at 256, and the widened RGB beams258, 260 and 262 are then projected through the SLMs 264, eachcontaining a spatially modulated signal according to the input picture.Then, the spatially modulated RGB beams 266, 268 and 270 are combined bya set of beam combiners (beam splitters) 272 into a white beam 274 thatpasses through an imaging lens 276, and the so-produced output beam 278is projected onto a screen surface 280, where the output image appears.This arrangement is generally known and by itself does not form part ofthe present invention, but can be utilized in the projecting device ofthe present invention as shown in FIGS. 1 and 6, and as further shown ina self-explanatory manner in FIG. 10B.

As shown in FIG. 10C, the RGB laser beams 290, 292 and 294 are timemodulated by a beam modulator 296 (prior to or after passage through abeam expander). Then, the time-modulated beam 298 is projected through asingle SLM 300. The spatially (and time) modulated beam 302 then passesthrough an imaging lens 304, and the so-produced output beam 306 isprojected onto a screen surface 308, where the output image appears.Similarly, this scheme is generally known and can be used in the deviceof the present invention. As shown in FIGS. 10D and 10E inself-explanatory manner, a diffractive element can be utilized by threetop-hat elements in front of the RGB laser beams 290, 292 and 294,respectively, or utilizing a common top-hat element.

The projecting device of the present invention can be used in variousapplications being connectable to and/or forming part of a computerdevice, such as PC, phone device, PDA, etc. FIGS. 11A to 11Hschematically illustrate different applications of the projecting deviceaccording to the invention.

In the example of FIG. 11A, the micro-projector device 138 of thepresent invention is used with a bi-directional semi-transparent screen136 of a laptop 134, and enables content viewing of images on both sidesof the screen. In the present example, the device 138 is supported by aholder 140, and is connected to a corresponding utility of the laptop toreceive an imaging signal to create a projected image 142 onto thescreen 136 to be viewed by two observers 144 and 148 at opposite sidesof the screen at two angles of observation 146 and 150, respectively.

FIG. 11B shows how the device of the present invention can be used withthe conventional laptop computer while eliminating the need for an LCDscreen typically used in these computers. To facilitate understanding,the same reference numbers are used to identify common components in theexamples of FIGS. 11A and 11B. As shown, the image is projected with anangle of projection 142 onto an external screen surface 160 opposite tothe user's eyes, i. e, to be viewed by the user with the angle ofobservation 164. It should be understood, although not specificallyshown, that the projector device 138 can be oriented to project theimage onto the table's surface adjacent to the computer, or onto theinner/outer surface of the laptop cover. Thus, user 144 while working ona portable laptop computer may advantageously operate with a largerscreen, or while operating on a computer with no display at all, canutilize the projector device of the present invention for imaging dataon an external surface. It should be understood that such projection ofimages on an external screen surface can be used with any communicationdevice, e.g., a phone device.

FIG. 11C exemplifies the use of several micro-projectors of the presentinvention, generally at 190, operable together to obtain a largeprojected screen 192 (video wall) by combining several small screens194, each produced by the corresponding one of the micro-projectors. Alarge image 198 is captured by a video camera 196 and transferred to theprocessor (image analyzer) 200 which operates to compare data indicativeof the large image 198 and data indicative of small images 194, andproduces an output signal to the controllers 202, causing them toreproduce the signal in such way that will cause the projectors 190 topresent the images 194 in alignment as a whole and seamless. The sameconfiguration can be used to project images onto a concave seamlessdisplay of any desired shape. This is schematically illustrated in FIG.11D. The main holder 206 holds several projector devices 204, each on aseparated branch holder 208. Each projector 204 projects a small image212 onto a concaved surface 210 to be viewed by an observer 216 as alarge concaved seamless image formed by small images partiallyoverlapping each other 214.

FIG. 11E illustrates the use of the present invention to project thesame image onto the opposite sides of a semi-transparent screen to beviewed by two users, while enabling to image on each of the screensurfaces an image intended for private use by the respective user. Inthis application, at least two persons 250 and 252 communicate face toface with each other around a desk 254, for example for the purpose of abusiness discussion or for playing a computerized game. Typically, thereis a graphical image that accompanies this communication, and bothparties need to see it and to contribute to it. Each party would like tokeep their own inputs to the joint image in their own custody, forpurposes of information security and for easy control. In is example,the person 250 has a micro-projecting device 258 that is associated witha control device 256. The projecting device 258 is supported by aspatial adjustment device 260 to project an image onto a verticalsemi-transparent screen 268 located between the two persons andsupported by a base 270. The other person 252 uses a similar projectingdevice 264 held by a support 266 and associated with a control device262 to project an image onto the vertical screen 268. Two projectedbeams 272 and 273 impinge onto the opposite faces of the screen 268, andcreate two different but well registered images. One projector isadjusted to project a mirror image of the data to be imaged, so thatboth images match each other. Person 250 sees an image, formed by thereflection of the beam 272 superimposed on the translucent beam 273,with a light collection angle 274, while the other person sees thereflected image 273 superimposed on the translucent image 272 with alight collection angle 276. Both persons see the same effective image.Each person can modify graphical information on its own projector, tocreate visual effects such as relationships between a mine and a tank ina war game, a drawing of a building and a layout of water pipes, a mapof a city and the layout of a new proposed residential complex, an X-rayof an anatomic organ and a scheme of a planned operation, etc.Registration marks in identical locations at the margins of the imagesserve to manually register the two images for exact overlap.

FIGS. 11F and 11G illustrate two examples, respectively, of yet anotherapplication of the present invention consisting of projecting stereoimages (it can be a non-stereoscopic projection, yet retinal one). Theuse of the micro-projector based on a spatially coherent light sourceallows obtaining a directional projection of images which cannot beobtained using the common incoherent projection devices. In the exampleof FIG. 11F, a user 310 is looking with his bare eyes into an opening320 of a stereoscopic projector 322. Two coherent projectors of thepresent invention using laser diodes as their light source 324 and 326are located inside the stereoscopic projector, each directed into theuser's eyes 312 and 314. The user, due to the human process ofinterpreting the images that both eyes see, conceives the two separatedimages 316 and 318 to be two projections of a three dimensional object.If the images produced by the two coherent projectors consist of astereoscopic image, the user will see a three dimensional scene. Thescene can be colored and can be dynamic. As shown, two projectors 324and 326 are connected via two data lines 328 and 330, and are connectedto a video input source (processor) 332 that synchronizes the two linesand their video data and determines which part of the data is to be sentto the respective one of the projectors in order to partially have someof the data shared between both of the projectors, but mainly toseparate the relevant data to the relevant projector within the unit.Two sources of video data 334 and 336 are two cameras standing andtaking shots from different angles of a single object 338 that is thenreproduced as a stereoscopic output image. It should be noted that thevideo sources can be of any kind, and the use of the cameras 334 and 336only demonstrates a given non-limited example.

Since the laser output is not projected onto a screen but to the user,the use of high optical output power is unnecessary and the opticalpower used is no more than the optical power which is constantly beingused in retinal projection goggles by Microvision Ltd., goggles that arealso known to be used in the U.S army.

The importance of using coherent light is associated with thepossibility of avoiding light dispersion without the need forcontrolling this effect, and the possibility of shifting the beam to adesired direction, while any other kind of light would be dispersed.

FIG. 11G shows an alternative implementation of the same concept,wherein a single projector is used. Here, in order to optimize the powerconsumption, a rotating mirror 352 is used to shift the beam angle andthereby produce the same effect as obtained with the two projectors ofFIG. 11F. This configuration saves the use of another projection unitand associated optics, and also saves footprint and weight of the entiresystem. The user is looking at the projecting device 350 while bothbeams 348 and 346 are directed to the user's eyes 342 and 344. Therotation of the beam between eye 342 and 344 is carried out by themirror 352 that continues to rotate in a high rate while the sync unit354 delivers the required data to each eye to create the 3D stereoscopiceffect to the user. Video data is delivered the same way as in theprevious example, but only one input video line 356 is connected to thesync unit that controls the input and the rotating mirror with adifferent control line 358.

The present invention can be used with wearable stereoscopic 3D glassesto provide a high efficiency 3D projection of images. This concept isschematically illustrated in FIG. 11H. In order to produce astereoscopic 3D image, it is typically required to have two projectionchannels operable to provide differences between the two images. In mostcommon systems, wearable glasses are used to maintain the requiredeffect. However, the glasses' lack of transmittance causes the degradingof a large portion of light returned to the observer's eye, resulting inthe reduction of brightness and a need for a more powerful projector.Using a DLP projector (Digital light processing projector, which is MEMStechnology based) in this specific application, results in a lowerefficiency and brightness to the eye of the user as compared to thatobtained with an LCD projector, even though that in general, theefficiency on the projected surface itself is higher that that obtainedwithout the 3D glasses. This is due to the fact that the glasses arepolarizer based, and since the light coming from an ordinary LCD systemis polarized, it passes through the glasses in a more efficient mannerwithout losing as much as if it had come with random polarization, [likefrom a micro-mirror modulator based projector (a DLP projector)], whenbeing reflected from the projected surface towards the observer glasses.

The technique of the present invention provides for improving the totalefficiency more than the both known concepts (Ordinary LCD, DMD/DLP), bysimple modification of the projector device of the present invention asexemplified in FIG. 1 or FIG. 6. The modification consists of removingthe polarizer in the output side of the SLM unit, thereby having nopolarizer at all (considering the use of the polarized light source).Hence, the projection image on the screen surface will not be visible tousers who don't wear the glasses and will be shown as a spot of light onthe surface. Users who wear the glasses and watch at the image, will seevery clearly the images since their glasses function as the polarizer inthe output side of the SLM. Consequently, a high brightness, highefficiency image will be obtained on the observer's 3D glasses.

It should be understood that all the functional elements of the deviceof the present invention as described above in its various implantationscan be integrated into a single hybrid component that can become anintegral part of a communication and computing device. The invention issuitable to be implemented with multiple light sources in order toproduce full color, or by the use of a white light source. The lightsource can be of any kind, for example a laser diode.

Those skilled in the art will readily appreciate that variousmodifications and changes can be applied to the embodiments of theinvention as hereinbefore exemplified without departing from its scopedefined in and by the appended claims.

1. An image projecting device comprising: a spatial light modulating(SLM) pixel arrangement having a pixel pitch substantially not exceeding50 μm and defining an active surface; first and second lens arraysrespectively located at opposite surfaces of said SLM pixel arrangementand being integral with said SLM pixel arrangement forming together withsaid SLM pixel arrangement a common SLM unit, such that each lens in thefirst array and a respective opposite lens in the second array areassociated with a corresponding one of the pixels, each of said firstand second lens arrays being implemented in a polymer spacer and eachbeing either spaced from the respective surface of the opposite surfacesof the pixel arrangement a predetermined distance or being in physicalcontact with said respective surface; a light source system (LSS)operable to produce an incident light beam of a predetermined crosssection corresponding to the size of said active surface; and amagnification optics accommodated at the output side of the SLM pixelarrangement.
 2. The device according to claim 1, wherein the distancebetween the lens array and the respective surface of the SLM pixelarrangement substantially does not exceed 50 μm.
 3. An image projectingdevice comprising: a spatial light modulating (SLM) pixel arrangementdefining an active surface; first and second lens arrays respectivelylocated at opposite surfaces of said SLM pixel arrangement and beingintegral with said SLM pixel arrangement, forming together with said SLMpixel arrangement a common SLM unit, such that each lens in the firstarray and a respective opposite lens in the second array are associatedwith a corresponding one of the pixels, each of said first and secondlens arrays being implemented in a polymer spacer and each being eitherspaced from the respective surface of the opposite surfaces of the pixelarrangement a distance substantially not exceeding 50 μm or being inphysical contact with said respective surface; a light source system(LSS) operable to produce an incident light beam of a predeterminedcross section corresponding to the size of said active surface; and amagnification optics accommodated at the output side of the SLM pixelarrangement.
 4. The device according to claim 3, wherein the SLM pixelarrangement comprises light modulating material defining said activesurface.
 5. The device according to claim 3, wherein the incident lightimpinging on to the SLM unit is specifically polarized, the devicecomprising a polarizer unit accommodated at the output side of the SLMpixel arrangement and having a preferred orientation of a plane ofpolarization so as to be either substantially the same as of theincident light beam or a 90-degree rotated with respect to that of theincident light beam.
 6. The device according to claim 5, wherein thelight source system includes a high-ratio polarized light source forgenerating the polarized incident light.
 7. The device according toclaim 5, comprising an input polarizer at the input side of the SLMpixel arrangement.
 8. The device according to claim 5, wherein saidpolarizer unit is constituted by the surface of wearable glasses capableof imitating a three-dimensional image.
 9. The device according to claim3, wherein the light source system comprises an optical arrangementoperable to provide substantially uniform intensity distribution withinthe cross-section of the incident light beam.
 10. The device accordingto claim 9, wherein said optical arrangement includes a diffractiveelement operable to modify the beam intensity distribution to producethe substantially uniform intensity distribution of the beam within itscross-section.
 11. The device according to claim 3 wherein the lightsource system includes a beam expander affecting the cross section of alight beam generated by the light source to provide the cross section ofthe beam substantially of the size of the active surface of the SLMunit.
 12. The device according to claim 3, wherein the light sourcesystem includes a light source generating a light beam of the crosssection substantially of the size of the active surface of the SLM unit.13. The device according to claim 3, comprising an image processorsystem operable to carry out at least one of the following: (i) applyingdigital processing to data indicative of an image to be projected so asto avoid or at least significantly reduce the speckles associatedeffects in the projected image; (ii) processing data indicative of theprojected image to correct for non-uniformities in the light intensity;and (iii) analyzing data indicative of the environmental condition toadjust at least one of the intensity and color mixture of the incidentlight beam.
 14. The device according to claim 13, comprising an imagerecorder operable to generate the data indicative of the projected imageand transmit said data to the image processor system.
 15. The deviceaccording to claim 13, comprising an environment sensor operable togenerate the data indicative of the environment condition and transmitsaid data to the image processor system.
 16. The device according toclaim 3, comprising a modulation driver responsive to an imaging signalrepresentative of an image to be projected, to generate modulationsignals to the SLM pixel arrangement.
 17. The device according to claim16, wherein said modulation driver is connectable to an image processorsystem to receive therefrom said imaging signal.
 18. The deviceaccording to claim 3, comprising a time modulator associated with saidSLM pixel arrangement and operable to apply time modulation to differentlight components of the light source system.
 19. The device according toclaim 18, wherein said different light components are different colorcomponents.
 20. The device according to claim 19, wherein said differentcolor components are formed by a combination of highly polarized andnon-polarized light.
 21. The device according to claim 20, wherein thelight source system includes at least one laser source for generatingpolarized light, and at least one light emitting diode for generatingnon-polarized light.
 22. The device according to claim 3, wherein thelight source system generates spatially separated different-color lightcomponents, the device comprising additional SLM pixel arrangements,each arrangement being associated with the corresponding one of thecolor light components.
 23. The device according to claim 3, comprisinga rotating mirror accommodated in front of a projecting surface, thedevice thereby enabling creation of a stereoscopic image.
 24. Aprojecting system comprising at least two projecting devices, eachconstructed according to claim
 3. 25. The system according to claim 24,comprising a control unit connectable to each of the projecting devicesand operable to enable creation of a large combined image on aprojecting surface formed by images created by the projecting devices.26. The system according to claim 25, wherein said projecting surface isconcave.
 27. The device according to claim 3, wherein said light sourcesystem comprises at least one coherent light source.
 28. A computersystem operable to generate data to be imaged, the system comprising animage projecting device connected to a data generating utility of thecomputer system and operating to project the image onto at least oneexternal projecting surface, said image projecting device comprising: aspatial light modulating (SLM) pixel arrangement defining an activesurface; first and second lens arrays respectively located at oppositesurfaces of said SLM pixel arrangement and being integral with said SLMpixel arrangement forming together with said SLM pixel arrangement acommon SLM unit, such that each lens in the first array and a respectiveopposite lens in the second array are associated with a correspondingone of the pixels, each of said first and second lens arrays beingimplemented in a polymer spacer and each being either spaced from therespective surface of the opposite surfaces of the pixel arrangement apredetermined distance or being in physical contact with said respectivesurface; a light source system (LSS) operable to produce an incidentlight beam of a predetermined cross section corresponding to the size ofsaid active surface; a magnification optics accommodated at the outputside of the SLM pixel arrangement.
 29. A method for projecting an imagecomprising: (i) providing a spatial light modulator (SLM) unitcomprising an SLM pixel arrangement having a pixel pitch substantiallynot exceeding 50 μm and defining an active surface; and first and secondlens arrays located at opposite surfaces of said SLM pixel arrangementand being integral with said SLM pixel arrangement, such that each lensin the first array and a respective opposite lens in the second arrayare associated with a corresponding one of the pixels, each of saidfirst and second lens arrays being implemented in a polymer spacer andbeing either spaced from the respective surface of the pixel arrangementa predetermined distance or being in physical contact with saidrespective surface; (ii) creating an incident light beam having apredetermined cross section corresponding to a size of said activesurface defined by the SLM pixel arrangement; (iii) passing said lightthrough the SLM unit and concurrently operating the SLM pixelarrangement with an imaging signal representative of an image to beprojected to thereby produce modulated light; (iv) passing the modulatedlight emerging from the SLM unit through a magnifying optics to beprojected onto a projecting surface.
 30. A method for projecting animage comprising: (i) providing a spatial light modulator (SLM) unitcomprising: a spatial light modulating (SLM) pixel arrangement definingan active surface; and first and second lens arrays located at oppositesurfaces of said SLM pixel arrangement and being integral with said SLMpixel arrangement, such that each lens in the first array and arespective opposite lens in the second array are associated with acorresponding one of the pixels, each of said first and second lensarrays being implemented in a polymer spacer and each being eitherspaced from the respective surface of the opposite surfaces of the SLMpixel arrangement a predetermined distance substantially not exceeding50 μm or being in physical contact with said respective surface; (ii)creating an incident light beam having a predetermined cross sectioncorresponding to a size of said active surface defined by the SLM pixelarrangement; (iii) passing said light through the SLM unit andconcurrently operating the SLM pixel arrangement with an imaging signalrepresentative of an image to be projected to thereby produce modulatedlight; (iv) passing the modulated light emerging from the SLM unitthrough a magnifying optics to be projected onto a projecting surface.31. The method according to claim 30, comprising providing specificpolarization of the incident light beam propagating towards the SLMpixel arrangement, and passing the modulated light, propagating towardsthe projecting surface, through a polarizer having a preferredorientation of a plane of polarization either substantially the same asthat of the incident light beam or a 90-degree rotated with respect tothat of the incident light beam.
 32. The method according to claim 31,comprising passing the randomly polarized light beam generated by alight source through a polarizer accommodated at the input side of theSLM pixel arrangement.
 33. The method according to claim 31, wherein theincident light beam is created by a high-ratio polarization lightsource.
 34. The method according to claim 30, wherein the incident lightbeam is created by a light source emitting a light beam with a crosssection substantially of the size of the active surface of the SLM pixelarrangement.
 35. The method according to claim 30, wherein the creationof incident light beam comprises passage of a light beam emitted by alight source through a beam shaping optics to thereby produce theincident light beam of the predetermined cross section.
 36. The methodaccording to claim 30, wherein the distance between the lens array andthe respective surface of the SLM pixel arrangement substantially doesnot exceed 50 μm.
 37. The method according to claim 30, comprisingproviding specific polarization of the incident light beam propagatingtowards the SLM pixel arrangement, and passing the modulated light,propagating towards the projecting surface, through a polarizer having apreferred orientation of a plane of polarization either substantiallythe same as that of the incident light beam or a 90-degree rotated withrespect to that of the incident light beam.
 38. The method according toclaim 37, comprising passing the randomly polarized light beam generatedby a light source through a polarizer accommodated at the input side ofthe SLM pixel arrangement.
 39. The method according to claim 37, whereinthe incident light beam is created by a high-ratio polarization lightsource.
 40. A method for projecting an image comprising: (i) providing aspatial light modulator (SLM) unit comprising: a spatial lightmodulating (SLM) pixel arrangement defining an active surface; and firstand second lens arrays respectively located at opposite surfaces of saidSLM pixel arrangement and being integral with said SLM pixelarrangement, such that each lens in the first array and a respectiveopposite lens in the second array are associated with a correspondingone of the pixels, each of said first and second lens arrays beingimplemented in a polymer spacer and each being either spaced from therespective surface of the opposite surfaces of the SLM pixel arrangementa predetermined distance or being in physical contact with saidrespective surface; (ii) creating an incident light beam having apredetermined cross section corresponding to a size of said activesurface defined by the SLM pixel arrangement; (iii) passing said lightthrough the SLM unit and concurrently operating the SLM pixelarrangement with an imaging signal representative of an image to beprojected to thereby produce modulated light; (iv) passing the modulatedlight emerging from the SLM unit through a magnifying optics to beprojected onto a projecting surface; (v) processing said imaging signalprior to operating thereby the SLM pixel arrangement, to apply digitaljittering and gray level processing of pixels, thereby enablingreduction of speckles' effects in the projected image.
 41. A method forprojecting an image comprising: (i) providing a spatial light modulator(SLM) unit comprising: a spatial light modulating (SLM) pixelarrangement defining an active surface; and first and second lens arraysrespectively located at opposite surfaces of said SLM pixel arrangementand being integral with said SLM pixel arrangement, such that each lensin the first array and a respective opposite lens in the second arrayare associated with a corresponding one of the pixels, each of saidfirst and second lens arrays being implemented in a polymer spacer andeach being either spaced from the respective surface of the oppositesurfaces of the SLM pixel arrangement a predetermined distance or beingin physical contact with said respective surface; (ii) creating anincident light beam having a predetermined cross section correspondingto a size of said active surface defined by the SLM pixel arrangement;(iii) passing said light through the SLM unit and concurrently operatingthe SLM pixel arrangement with an imaging signal representative of animage to be projected to thereby produce modulated light; (iv) passingthe modulated light emerging from the SLM unit through a magnifyingoptics to be projected onto a projecting surface; (v) obtaining dataindicative of the projected image, analyzing said data and processingsaid imaging signal prior to operating thereby the SLM pixelarrangement, to thereby provide substantially uniform intensity withinthe projected image.
 42. A method for projecting an image comprising:(i) providing a spatial light modulator (SLM) unit comprising: a spatiallight modulating (SLM) pixel arrangement defining an active surface; andfirst and second lens arrays respectively located at opposite surfacesof said SLM pixel arrangement and being integral with said SLM pixelarrangement, such that each lens in the first array and a respectiveopposite lens in the second array are associated with a correspondingone of the pixels, each of said first and second lens arrays beingimplemented in a polymer spacer and each being either spaced from therespective surface of the opposite surfaces of the SLM pixel arrangementa predetermined distance or being in physical contact with saidrespective surface; (ii) creating an incident light beam having apredetermined cross section corresponding to a size of said activesurface defined by the SLM pixel arrangement; (iii) passing said lightthrough the SLM unit and concurrently operating the SLM pixelarrangement with an imaging signal representative of an image to beprojected to thereby produce modulated light; (iv) passing the modulatedlight emerging from the SLM unit through a magnifying optics to beprojected onto a projecting surface; (v) obtaining data indicative of anenvironment condition, analyzing said data, and processing said imagingsignal prior to operating thereby the SLM pixel arrangement, to therebyadjust at least one of the intensity and color mixture of the modulatedlight forming the projected image.